Auditoriums · SERVICE · REV 2026-10-06
Auditorium construction
Auditorium construction is installing the rake, the seats, the envelope, and AV routes while the room is still a site. The seat is not used to hide unfinished work, and capacity is not extracted from area during the pour.
Definition
The page assumes design has fixed the rake, the sightline, and the speech criterion. Site work is step levels, an anchor that does not wreck a floating floor if there is one, doors that close the envelope, and routes buried before the ceiling. An RT60 measurement in bare concrete is not a handover. ISO 3382-1 and IEC 60268-16 are used by the method the brief wrote, after the agreed condition is complete.
This is not a supply of loose chairs on a flat floor, and not a late design for a concert hall. If the section is a draft, starting the seats is the wrong scope. The page states no STC, no fire class, and no kilopascal figure. The adopted code, product reports, and measurement are the reference. The page does not replace them.
When is this service needed?
The section is issued for construction
The steps and the number of seats between aisles are no longer an idea.
The room is still open
A level or a route can still be repaired before the ceiling and the step close.
Seats are fixed, not lined up
The anchor and the load are part of the slab. Loose supply is a different scope.
Wrong scope
An unsigned rake, loose furniture named a hall, or a request for an occupancy certificate from a knowledge page.
Where it is used
A cast or built rake
Concrete or steel carries the step. Tolerance stacks up to the seat.
A hall inside an existing building
The old level may not accept the rake. A survey comes before the order.
An envelope next to a noisy void
The door, the ceiling, and the void above are a path. Finish alone does not close it.
A site shared with general finishes
The seat is damaged and dust changes the measurement. Sequence protects the sample.
Parts of the solution
The rake body
Tread, nosing, and riser. It matches the section after finish, not only before it.
Seat anchor
Its place comes from the seat maker. Its penetration of a floating floor is detailed so it does not short the isolation.
Envelope: door, ceiling, rear wall
Seals and openings are part of speech. A door gap raises the noise floor.
AV routes
Containment for the platform, the ceiling, and a hearing loop before the pour or before close-up.
Protection until handover
A seat on a building site gets dirty and breaks. Protection is an item, not a courtesy.
Engineering considerations
Tolerance kills the line
A few millimetres on each step become a head that blocks at the last row. The tolerance limit is on the drawing.
Anchor and load
A fixed chair and a crowd are a structural load. The page publishes no load figure.
Do not short a floating floor
A bolt to the structural slab brings the noise path back. The detail comes before the drilling.
Measure in the final condition
Seats, doors, and HVAC as in a lecture. Anything else is a site note.
Egress during installation
Seat storage does not close an exit. The code applies to the later occupied room and to the work now.
Materials
Step body
Concrete, steel, or composite as the structural engineer has it. The page chooses neither a system nor its fire class.
Tread finish
Slip resistance and a visible nosing are a safety requirement from the code and the product report, not from this page.
Door and ceiling seals
Materials that match both the acoustic detail and the fire detail, on their own documents.
Related systems
Lectern infrastructure
Power, signal, and a microphone route are closed before the platform face is finished.
Loudspeakers and ceiling
Fixing points are coordinated with reflectors, not added after the cut.
Hearing loop
The cable sits where random steel will not kill it. Design stays on the loop page.
HVAC
The damper and silencer are installed before the ceiling closes if they are in the brief. There is no NC curve here.
Design sequence
- 01
Read the signed section and mark the levels the contractor will be held to after finish.
- 02
Match the seat detail to the floor: floating or solid, load, and aisle edge.
- 03
Draw the routes that must be buried: platform, ceiling, loop, and power.
- 04
Define the measurement condition for handover: seats, doors, HVAC, and the named standard method.
- 05
Agree a sample row before releasing the whole order.
Delivery sequence
- 01
Form the rake and verify levels before any seat.
- 02
Run the routes and close the penetrations that will not be seen again.
- 03
Install a sample, and check view, aisle, and fixing.
- 04
Complete the seats with protection, and do not use them as a working aisle.
- 05
Measure after balance and adjustment, not in an open shell that is then called final.
Testing
Levels against the drawing
The finished step, not only the rough concrete. The acceptance limit is in the documents, not here.
A sightline and row sample
A real sitter or an agreed eye height, from the start of the row and the end.
Measurement of the final condition
RT60 to ISO 3382-1 and STI to IEC 60268-16 if the brief wrote them. No pass figure from this page.
Commissioning
A technical snag list
Level, seal, route, and a seat that rocks. Not fabric colour alone.
HVAC running with the measurement
If speech is the programme, handover and noise are in the same mode.
A record, not a page certificate
This page grants neither occupancy nor a hall accreditation.
Maintenance
Removing a seat for repair
The anchor goes back as detailed. A random plug can short a floating floor.
Repainting the tread
Thickness builds up and changes the level. Review it if it grows.
A door that lost its closer
The acoustic envelope is practically open. Noise returns before anyone notices it in a measurement.
Common mistakes
Seats on a draft section
Wrong scope. The envelope and the anchors are wasted when the rake moves.
Hiding incomplete work with chairs
The seat is not a cover for an open duct or a wrong step.
A shell measurement as handover
RT60 will change with fabric and the door. An early record is not acceptance.
Loose furniture called hall construction
If there is no rake, no envelope, and no load, the scope is furniture, not this page.
Short comparison
The comparison is a way to choose a path. It is not a product recommendation and it is not a code.
| Path | Fits when | Weakens when |
|---|---|---|
| Cast the rake | The section is frozen and the structure can form it. | When the sightline is still a sketch. |
| Seats on a finished step | The envelope and the anchors are coordinated. | When the room is an open site and the seats hide unfinished work. |
| Loose chairs on a flat floor | The brief is furniture, not a raked Auditorium. | When those chairs are later called a designed hall. |
Discussion ranges
Any number here is a preliminary discussion range from practice or a named reference. Replace it with the project criterion, laboratory data, and on-site measurement.
| Item | What is discussed | Limit of this page |
|---|---|---|
| Rake tolerance | The built step must match the sightline section after finish. | Limit: no allowable millimetre is published here. The drawing and the seat maker set it. |
| Anchor in a floating floor | An anchor that reaches the structural slab can cancel the isolation that was paid for. | Limit: no STC. The detail prevents the bridge, and verification follows the method written in the brief. |
| RT60 at handover | Discussed as a project criterion after the seats, not in the bare shell. | Limit: no seconds here. Measure to ISO 3382-1 in the named condition. |
| Background noise | Discussed as a curve in the HVAC mode the audience will hear. | Limit: no NC or NR figure. The curve is written in the brief and measured there. |
What this page does not claim
No fire classification, absorption coefficient, sound pressure level, or legal capacity on this page may be copied into a quotation. Those values come from a product test report, a measurement, or the local code adopted for the project.
Questions designers and owners ask
Do we install seats while the drawing is changing?
No. That is the wrong scope. Rake, anchors, and envelope are wasted, and a sightline is not repaired by upholstery.
When is a measurement acceptable for handover?
After the condition the brief named is complete: seats, doors, and HVAC. ISO 3382-1 and IEC 60268-16 are not replaced by a shell visit.
Is a floating floor drilled for the seat?
Only with a detail that does not bridge the gap to the slab. A direct bolt brings the noise back. The page does not offer an STC as a cure.
Who sets the seat load?
The structural engineer, with the maker's data and the adopted code. This page refuses to publish a kilopascal figure to be copied into a contract.
Is a supply of loose chairs on a flat floor enough?
If the ask is a raked Auditorium with an envelope, no. That is a furniture scope, and calling it hall construction is wrong.
Technical sources
- ISO 3382-1
Measurement of room parameters after completion. The page does not replace the standard and does not treat a shell measurement as handover.
- IEC 60268-16
If speech intelligibility is a handover item, the STI method is here. The page sets no score and does not replace the document.
- The building, fire, and egress code adopted by the project
Levels that affect safety, exits during installation, and material performance. The page names no city and no product class.
Last editorial review: 2026-10-06. Review means the text was checked, not that a project was measured.
Turn the question into a brief
A study starts from room volume, use, and existing condition, not from a product name. Fill the brief and copy it.
Project study form